Fruit orchards are often subject to frost or freezing conditions which result in damage to the fruit or the buds/blossoms. There are several well known ways for preventing such damage, including wind machines, which move the cold air which collects about the trees, large sprayers which spray the fruit with water, and heaters of various types. An example of an orchard heater which produces heated steam is shown in U.S. Pat. No. 5,010,872 to Kish et al. That heater uses liquid propane to produce very moist hot air which is useful in protecting fruit trees from frost damage, including in particular damage to buds and blossoms. However, that heater has proven to have some difficulties with ignition and is rather cumbersome to ignite efficiently when a large number of such heaters must be ignited in succession.
A related need concerns efficient heating for large, enclosed spaces (but well-ventilated), such as manufacturing plants, automobile repair shops, etc. In these environments, an efficient source of heated dry air is desirable.
In both situations, convenient ignition and reliable and efficient operation are important, as well as the overall economy of the apparatus and the durability thereof.